code: def _rand_string(size=6) -> str:
      alphabet = string.ascii_letters + string.digits
      # noinspection PyShadowingBuiltins
      return "".join([random.choice(alphabet) for _ in range(size)])
  
file_path: lets-plot/python-package/lets_plot/frontend_context/_jupyter_notebook_ctx.py
imports: import os
  import pkgutil
  import random
  import string
  from typing import Dict
  from ._frontend_ctx import FrontendContext
  from ..None import _kbridge
  from .._global_settings import get_js_cdn_url
  from .._global_settings import JS_BASE_URL, JS_NAME
  from .._version import __version__
label_desc: Use image node_id 6 for calling the JupyterNotebookContext obj's underlying member method code with example usage: obj._rand_string(size) and returns: str